I was wondering what model car used the G54B motor?
If so, were they sent to the US?

some motors were turboed

seach so far says
dodge challenger
The US market G54B 2.6 Starion/Conquest used the TD05-12A however with a 8cm2 ... Ralliart TD06-19C turbo used on factory Pajero/Starion G54B 2.6 litre ...

are there any other ?

The 4G54 , 4G56 were common in older Pajeros , Starions , Strada/Forte/Triton, Lancer , and Galant (RWD) models in Thailand in Turbo and carb and fuel injection and turbo intercooled models frum the 80 to about 92 when the 4G64 and other TD models totally replaced them.

Lots of the Pajeros/Strada/Triton/Forte were the 4G54 with turbo and intercooled as well as the 4G54 NA and also a 4G56 turbo in house Tuned in Thailand(SWB onlee) as well as Ralliart upgrades.

Starion and Galants got 4G54 and 4G56 in NA turbo or in house tuned in the 80's with Ralliart offered parts between 84-86 before the Galant Changed to FWD/AWD in 86 for 87 model year. Altho they did not offer an intercooler as did the truck/suv models , but can be fitted on the Starion ( The 4G63 replaced the 4G56 in about 83 up in both models as a NA engine option over the 4G56)

The Mitsubishi Lancer(rwd) were offered with the 4G56 and NA 4G54 engines and top model 4G54 Turbo and intercooler thru 85-88 as well as an 4G63 turbo option

dont 4get montero's, raiders, K-cars, caravans, mitey max, d-50's, and quiet a few mitsubishi
forklifts used the g54b also.